Solvent-free mechanochemical synthesis of TiO2-ethyl cellulose biocomposite for adsorption of tetracycline and organic dyes

Abstract

In the study, polymeric-metal oxide hybrid composite was synthesized by mechanochemical method in ball-mill by adding different amounts of TiO2 to ethyl cellulose (EC) and its potential in tetracycline (TC) removal from aqueous solutions was investigated. In order to investigate the adsorption capacity, isotherm, kinetic and thermodynamic parameters of the adsorption process, the amount of adsorbent, contact time, solution pH, temperature effect, inert electrolyte effect and different water environment effects were experimentally carried out in batch adsorption experiments. The adsorption capacity of all sorbents was conformed according to the Freundlich isotherm model and the maximum capacity is found for 80%TiO2@EC with 23.26 mg g−1. The system reached equilibrium with 89% TC removal in 480 min and complied with the pseudo second order kinetic model. In the pH effect experiments, maximum TC removal found in pH:6. Thermodynamic parameters indicate that TC adsorption on 80%TiO2@EC is endothermic and spontaneous. Different water medium and inert electrolyte effect were found compatible with each other. Also, a decrease was observed in the specific TC removal in the presence of any ions in the system. The removal of methylene blue (MB) and malachite green (MG) azo dyes as another organic environmental pollutant was also studied and their adsorption capacities were found as 105.7 mg g−1 and 109.9 mg g−1, respectively. XRD, FTIR and SEM analyzes were performed to explain the interaction mechanism between sorbent samples and TC.